All Souls College, Oxford University. The All Souls fellows exam is dropping its most gruelling element - the one-world essay question. Photograph: Graham Turner for the Guardian

It is thought to be the hardest exam in the world. For almost a century, just a handful of the brightest young Oxford graduates have been picked to sit it each year and often only one is successful.

But this year, for the first time, the All Souls fellows exam is dropping its most gruelling element – the one-word essay question. The task has defeated even the most brilliant of minds in requiring them to open an envelope, inside which is a card with a single word – for instance, innocence or morality – and to write coherently about the subject for three hours.

The historian Lord Dacre and the author Hilaire Belloc were not up to the challenge, unlike the philosopher Sir Isaiah Berlin and the judge Richard Wilberforce. Those who excel, and who succeed in four other – more conventional – papers, are admitted to Oxford University's graduate-only college, All Souls.

The title All Souls fellow propels them, in their early 20s, to academic stardom. Fellowship lasts for seven years and comes with a stipend of £14,783 a year.

The one-word essay holds such mystique that crowds are said to gather outside the ancient university's exam hall to learn which word has been set. Past titles have been water, miracles and bias.

So it is after much consideration that the college's dons have voted to scrap it.

Sir John Vickers, the head of All Souls and former member of the Bank of England's monetary policy committee, said that in recent years the essay had "not proved so useful" as a test of the qualities for admission – namely "exceptional analytical ability, breadth and depth of knowledge, independent-mindedness and clarity of thought and expression".

The remaining four exams are a mix of general papers, and subject papers such as English literature, law and classics.

"We have dropped it with some regret. It was the part of the exam where everyone did the same thing, but experience shows that we get more insight into candidates' abilities when they are free to choose from question papers," said Vickers.

Professor Terence Kealey, who studied for his doctorate at Oxford and is vice-chancellor of the University of Buckingham, said it was a great shame to drop the paper. "The one-word question tests an individual's creativity while forcing them to align with scholarly rigour," he said.

Robin Briggs, a historian and emeritus fellow at All Souls, who passed the exam in 1964, aged 22, said it was "too esoteric, even for Oxford". Just remembering the ordeal makes him shudder, he said. In his year, the word was innocence.

Elizabeth Chatterjee, 23, who passed in 2008 when the word was novelty, said that in her year candidates spent the first hour wandering around the exam hall, thinking and sipping water.